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-rw-r--r--fs/btrfs/root-tree.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
new file mode 100644
index 00000000000..b48650de447
--- /dev/null
+++ b/fs/btrfs/root-tree.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "ctree.h"
+#include "transaction.h"
+#include "disk-io.h"
+#include "print-tree.h"
+
+/*
+ * search forward for a root, starting with objectid 'search_start'
+ * if a root key is found, the objectid we find is filled into 'found_objectid'
+ * and 0 is returned. < 0 is returned on error, 1 if there is nothing
+ * left in the tree.
+ */
+int btrfs_search_root(struct btrfs_root *root, u64 search_start,
+ u64 *found_objectid)
+{
+ struct btrfs_path *path;
+ struct btrfs_key search_key;
+ int ret;
+
+ root = root->fs_info->tree_root;
+ search_key.objectid = search_start;
+ search_key.type = (u8)-1;
+ search_key.offset = (u64)-1;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+again:
+ ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret == 0) {
+ ret = 1;
+ goto out;
+ }
+ if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret)
+ goto out;
+ }
+ btrfs_item_key_to_cpu(path->nodes[0], &search_key, path->slots[0]);
+ if (search_key.type != BTRFS_ROOT_ITEM_KEY) {
+ search_key.offset++;
+ btrfs_release_path(root, path);
+ goto again;
+ }
+ ret = 0;
+ *found_objectid = search_key.objectid;
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * lookup the root with the highest offset for a given objectid. The key we do
+ * find is copied into 'key'. If we find something return 0, otherwise 1, < 0
+ * on error.
+ */
+int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root_item *item, struct btrfs_key *key)
+{
+ struct btrfs_path *path;
+ struct btrfs_key search_key;
+ struct btrfs_key found_key;
+ struct extent_buffer *l;
+ int ret;
+ int slot;
+
+ search_key.objectid = objectid;
+ search_key.type = BTRFS_ROOT_ITEM_KEY;
+ search_key.offset = (u64)-1;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+ ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ BUG_ON(ret == 0);
+ l = path->nodes[0];
+ BUG_ON(path->slots[0] == 0);
+ slot = path->slots[0] - 1;
+ btrfs_item_key_to_cpu(l, &found_key, slot);
+ if (found_key.objectid != objectid) {
+ ret = 1;
+ goto out;
+ }
+ read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
+ sizeof(*item));
+ memcpy(key, &found_key, sizeof(found_key));
+ ret = 0;
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * copy the data in 'item' into the btree
+ */
+int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_key *key, struct btrfs_root_item
+ *item)
+{
+ struct btrfs_path *path;
+ struct extent_buffer *l;
+ int ret;
+ int slot;
+ unsigned long ptr;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+ ret = btrfs_search_slot(trans, root, key, path, 0, 1);
+ if (ret < 0)
+ goto out;
+
+ if (ret != 0) {
+ btrfs_print_leaf(root, path->nodes[0]);
+ printk(KERN_CRIT "unable to update root key %llu %u %llu\n",
+ (unsigned long long)key->objectid, key->type,
+ (unsigned long long)key->offset);
+ BUG_ON(1);
+ }
+
+ l = path->nodes[0];
+ slot = path->slots[0];
+ ptr = btrfs_item_ptr_offset(l, slot);
+ write_extent_buffer(l, item, ptr, sizeof(*item));
+ btrfs_mark_buffer_dirty(path->nodes[0]);
+out:
+ btrfs_release_path(root, path);
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_key *key, struct btrfs_root_item
+ *item)
+{
+ int ret;
+ ret = btrfs_insert_item(trans, root, key, item, sizeof(*item));
+ return ret;
+}
+
+/*
+ * at mount time we want to find all the old transaction snapshots that were in
+ * the process of being deleted if we crashed. This is any root item with an
+ * offset lower than the latest root. They need to be queued for deletion to
+ * finish what was happening when we crashed.
+ */
+int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid,
+ struct btrfs_root *latest)
+{
+ struct btrfs_root *dead_root;
+ struct btrfs_item *item;
+ struct btrfs_root_item *ri;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_path *path;
+ int ret;
+ u32 nritems;
+ struct extent_buffer *leaf;
+ int slot;
+
+ key.objectid = objectid;
+ btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+ key.offset = 0;
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+again:
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto err;
+ while (1) {
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ slot = path->slots[0];
+ if (slot >= nritems) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret)
+ break;
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ slot = path->slots[0];
+ }
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (btrfs_key_type(&key) != BTRFS_ROOT_ITEM_KEY)
+ goto next;
+
+ if (key.objectid < objectid)
+ goto next;
+
+ if (key.objectid > objectid)
+ break;
+
+ ri = btrfs_item_ptr(leaf, slot, struct btrfs_root_item);
+ if (btrfs_disk_root_refs(leaf, ri) != 0)
+ goto next;
+
+ memcpy(&found_key, &key, sizeof(key));
+ key.offset++;
+ btrfs_release_path(root, path);
+ dead_root =
+ btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
+ &found_key);
+ if (IS_ERR(dead_root)) {
+ ret = PTR_ERR(dead_root);
+ goto err;
+ }
+
+ if (objectid == BTRFS_TREE_RELOC_OBJECTID)
+ ret = btrfs_add_dead_reloc_root(dead_root);
+ else
+ ret = btrfs_add_dead_root(dead_root, latest);
+ if (ret)
+ goto err;
+ goto again;
+next:
+ slot++;
+ path->slots[0]++;
+ }
+ ret = 0;
+err:
+ btrfs_free_path(path);
+ return ret;
+}
+
+/* drop the root item for 'key' from 'root' */
+int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_key *key)
+{
+ struct btrfs_path *path;
+ int ret;
+ u32 refs;
+ struct btrfs_root_item *ri;
+ struct extent_buffer *leaf;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+ ret = btrfs_search_slot(trans, root, key, path, -1, 1);
+ if (ret < 0)
+ goto out;
+
+ BUG_ON(ret != 0);
+ leaf = path->nodes[0];
+ ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);
+
+ refs = btrfs_disk_root_refs(leaf, ri);
+ BUG_ON(refs != 0);
+ ret = btrfs_del_item(trans, root, path);
+out:
+ btrfs_release_path(root, path);
+ btrfs_free_path(path);
+ return ret;
+}
+
+#if 0 /* this will get used when snapshot deletion is implemented */
+int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *tree_root,
+ u64 root_id, u8 type, u64 ref_id)
+{
+ struct btrfs_key key;
+ int ret;
+ struct btrfs_path *path;
+
+ path = btrfs_alloc_path();
+
+ key.objectid = root_id;
+ key.type = type;
+ key.offset = ref_id;
+
+ ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
+ BUG_ON(ret);
+
+ ret = btrfs_del_item(trans, tree_root, path);
+ BUG_ON(ret);
+
+ btrfs_free_path(path);
+ return ret;
+}
+#endif
+
+int btrfs_find_root_ref(struct btrfs_root *tree_root,
+ struct btrfs_path *path,
+ u64 root_id, u64 ref_id)
+{
+ struct btrfs_key key;
+ int ret;
+
+ key.objectid = root_id;
+ key.type = BTRFS_ROOT_REF_KEY;
+ key.offset = ref_id;
+
+ ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
+ return ret;
+}
+
+
+/*
+ * add a btrfs_root_ref item. type is either BTRFS_ROOT_REF_KEY
+ * or BTRFS_ROOT_BACKREF_KEY.
+ *
+ * The dirid, sequence, name and name_len refer to the directory entry
+ * that is referencing the root.
+ *
+ * For a forward ref, the root_id is the id of the tree referencing
+ * the root and ref_id is the id of the subvol or snapshot.
+ *
+ * For a back ref the root_id is the id of the subvol or snapshot and
+ * ref_id is the id of the tree referencing it.
+ */
+int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *tree_root,
+ u64 root_id, u8 type, u64 ref_id,
+ u64 dirid, u64 sequence,
+ const char *name, int name_len)
+{
+ struct btrfs_key key;
+ int ret;
+ struct btrfs_path *path;
+ struct btrfs_root_ref *ref;
+ struct extent_buffer *leaf;
+ unsigned long ptr;
+
+
+ path = btrfs_alloc_path();
+
+ key.objectid = root_id;
+ key.type = type;
+ key.offset = ref_id;
+
+ ret = btrfs_insert_empty_item(trans, tree_root, path, &key,
+ sizeof(*ref) + name_len);
+ BUG_ON(ret);
+
+ leaf = path->nodes[0];
+ ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
+ btrfs_set_root_ref_dirid(leaf, ref, dirid);
+ btrfs_set_root_ref_sequence(leaf, ref, sequence);
+ btrfs_set_root_ref_name_len(leaf, ref, name_len);
+ ptr = (unsigned long)(ref + 1);
+ write_extent_buffer(leaf, name, ptr, name_len);
+ btrfs_mark_buffer_dirty(leaf);
+
+ btrfs_free_path(path);
+ return ret;
+}